Simple Interest Calculator
Interest on a principal amount at a flat annual rate.
Overview
Computes flat-rate non-compounding interest on principal loans, bonds, short-term promissory notes, and informal credit.
Formula & Calculation Method
SI = (P × R × T) / 100 | Maturity = P + SI
P = Principal sum, R = Annual interest rate %, T = Time period in years.
Worked Example: ₹50,000 at 8% Simple Interest for 3 Years
Inputs: Principal = ₹50,000 | Rate = 8% p.a. | Time = 3 Years
- Interest calculation = (50,000 × 8 × 3) / 100
- Total interest earned = ₹12,000
- Total maturity sum = ₹50,000 + ₹12,000 = ₹62,000
Summary: Principal = ₹50,000 | Simple Interest = ₹12,000 | Maturity Amount = ₹62,000
Common Use Cases
- Informal Borrowing: Calculate flat interest between family, friends, or private lending agreements.
- Government Bonds: Compute coupon payouts on fixed-rate treasury securities.
- Late Payment Penalties: Assess statutory interest charges on delayed commercial invoices.
Frequently Asked Questions
Where is simple interest still used in modern banking?
It is used for short-term treasury bills, certain government savings schemes, and penalty interest on overdue payments.
Why does simple interest produce lower returns than compound interest?
Because earned interest does not get reinvested to earn additional interest in subsequent periods.
How do I calculate simple interest for 6 months?
Input time T as 0.5 years (6 / 12) in the formula.
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